Dimensionless coefficients of vertical dust diffusion δ_z calculated from the time-averaged root mean square z_d,rms (circles) and standard deviation σ_zd (squares) of the vertical dust particle positions (left panel). Dimensionless radial dust diffusion coefficients δ_r computed considering all dust particles that are initially located within Δr_init = 0.1 au (circles) or Δr_init = 0.01 au (squares). In both panels, open and filled symbols represent simulations with a dust size of 3 mm and 3 cm, respectively. Simulations of only the vertical shear instability, only the streaming instability, the scenario SIwhileVSI, and the scenario SIafterVSI are depicted using blue, orange, green, and purple markers, respectively. We note that the vertical diffusion coefficients in the vertical shear instability simulation with the larger dust size fall outside of the ordinate range and are therefore plotted in an inset with a different ordinate.